As a bride and/or client there are a certain things that are expected when it comes to your reception. I have outlined a few.
1-Enough food - if you tell the caterer how many guests you expect then then should provide enough food to feed everyone. They should have about 15% over just in case some 'extra' guests show up. The food should be hot and they should be able to provide for any allergy or food issues with your guests.
2-To go along with enough food should also be appropriate place settings and water glasses with water in them. Whether this is a backyard BBQ or a 5 course meal the caterer should provide plates, silverware and glassware.
3-Linens - if you are getting in house linens they should be clean and unsoiled. They should not have creases in them; they should not be visibly wrinkled. Make it clear that you want ironed linens and that they much touch the floor. One of my biggest peeves is square linens on a round table showing off the metal legs.
4-The sales person or caterer should listen to you and make every effort to make your wedding the way you want it not just like all the other weddings done there.
5-Staff - the reception site should provide adequate wait staff and they should be nice and do what ever is necessary to make your guests happy.
6-And lastly remember you get what you pay for. I am not suggesting you have to spend a lot of money but just remember what you deserve and make sure you are paying appropriately for it.